The present invention relates to a playback apparatus which allows one of a variety of playback modes to be selected in a playback operation of a disc-shaped recording medium containing recorded main data and recorded sub-data.
As a recording apparatus and/or a playback apparatus for recording and/or play back data such as music respectively, there has been known a recording apparatus and/or a playback apparatus which uses a magnetic optical disc or a magnetic tape for recording an audio signal as a digital signal as recording media.
In addition, in a recording and playback system using a magnetic optical disc known as a mini disc (a trademark), the user is capable of not only recording and playing back musical data such as a song as a program but also the title of the disc (or the name of the disc), the names of a song (or the name of a track) and the name of an artist for the program or musical data recorded on the disc as character information. Thus, in a playback operation, information such as the title of a disc, the name of a song or the name of an artist can be displayed on a display unit provided on the playback apparatus.
It should be noted that the term xe2x80x98programxe2x80x99 used in this specification is a unit of typically audio data such as songs recorded on a disc as main data. Typically, audio data of a song is treated as a program. In addition, the word xe2x80x98trackxe2x80x99 is used with the same meaning as the term xe2x80x98programxe2x80x99.
As for the mini-disc system, the patent applicant earlier proposed a configuration wherein a recording area for recording sub-data associated with audio data recorded as main data is provided separately from a recording area for recording the main data, and sub-data such as still-picture data and character data can be recorded into the separately provided recording area. It should be noted that, in this specification, the term xe2x80x98charactersxe2x80x99 include symbols and notations.
Also in the conventional mini-disk system, for example, character information such as the name of a disc and the name of a track can be recorded. In this case, however, these pieces of character information are recorded for each program in a U-TOC (User Table of Contents). It should be noted, however, that the size of the U-TOC itself is not that big. Thus, to the bitter end, only characters of no more than a title or the like can be recorded as described above.
In the case of the proposed configuration, on the other hand, a recording area for sub-data is provided. Thus, not only can character data be accommodated therein, but an operation to record data such as a still picture as a data file can also be implemented with ease provided that the still-picture data does not require an area with such a large storage size.
As a possible way to utilize sub-data such as a picture or character information in a mini-disc system with a configuration allowing sub-data to be recorded in addition to audio data which is recorded as main data as described above, for example, for a period of time to play back a program recorded as main data, timing to play back a data file containing a piece of sub-data or a plurality of pieces of sub-data is prescribed in advance so that the data file can be played back and output in synchronization with the operation to play back the program.
To put it concretely, let us assume for example that a piece of music with a performance length of 2 minutes is stored as main data on a disc along with still-picture files containing 2 pictures, namely, Pictures #1 and #2 respectively which are stored as sub-data associated with the piece of music. For a period of time to play back this main data, the timing to play back Pictures #1 and #2 in synchronization with the main data is prescribed in advance. According to the prescribed synchronous playback timing, during the former half of the period of time to play back the audio data of the program (that is, the piece of music), the still-picture file of Picture #1 is played back in synchronization with the operation to play back the program to output a display. During the latter half of the period of time to play back the audio data of the program, on the other hand, the still-picture file of Picture #2 is played back in synchronization with the operation to play back the program to output a display.
It should be noted that sub-data such as a still-picture file played back in synchronization with the operation to play back a program as described above is actually output to, for example, a display panel provided on the mini-disc recording and playback apparatus or an external monitor unit to be displayed thereon.
With a configuration allowing such a synchronous playback operation to be carried out, the user is capable of enjoying the playback apparatus by not only listening to main data which is played back as audio data but also watching a still picture and character information displayed along with the progress of the reproduced piece of music.
Considering the actual use of a recording and playback apparatus adopting a configuration capable of playing back and outputting not only audio data but also a character-information file and a picture file recorded as sub-data associated with the audio data as described above, it is desirable to utilize the characteristics of the configuration as effectively as possible in the user-amusement aspect and the functional aspect of the recording and playback apparatus.
Let amusement for the user be taken into consideration for example. In this case, rather than always playing back and outputting audio data recorded as main data along with a character-information file and a picture file recorded as sub-data, the following alternative configuration is desirable. In this alternative configuration, for example, the user is allowed to select the type of data to be played back.
That is to say, for instance, only audio data is played back as is the case with the conventional system, or only a character-information file and a picture file which are recorded as sub-data can be played back. This alternative configuration is desirable in that the user is allowed to select one among a variety of ways to play back and output data.
In addition, the following improvement in the functional aspect is also conceivable.
The mini-disc recording and playback apparatus is provided with a buffer memory used for temporarily holding audio data read out from a disc. The buffer memory is placed on a data playback path between the disc and a playback-output system. In this configuration, by setting the transfer speed of audio data transferred from the disc to the buffer memory at a value higher than the transfer speed of audio data transferred from the buffer memory to the playback-output system, audio data will get accumulated in the buffer memory. In actuality, when the buffer memory becomes full of audio data or when the amount of audio data accumulated in the buffer memory exceeds a predetermined value, the operation to transfer audio data from the disc to the buffer memory is temporarily halted. Thus, audio data is played back from the disc intermittently. With such a buffer memory, a continuous operation to transfer audio data from the buffer memory to the playback/output system is assured to improve a vibration-proof characteristic of the mini-disc recording and playback apparatus which is one of the natural design objectives of the apparatus.
Assuming that an intermittent playback operation cited above is an operation to read out main data and sub-data from an actual disc with the sub-data read out in synchronization with the main data as described earlier, in the present patent application, the following configuration is proposed.
During a period in which an operation to transfer audio data from the disc to the buffer memory is paused in an intermittent playback of audio data described above, an access to a sub-data area on the disc is made to read out a necessary sub-data file from the disc and play back and output sub-data contained in the file. In such a playback operation, sub-data files necessary in the synchronous playback can be obtained sequentially one file after another for example while main data is being played back. It is thus no longer necessary to read out all sub-data files required in the synchronous-playback operation from the disc and keep sub-data recorded in the files in the buffer memory for example at a stage before starting the operation to play back main data. As a result, the length of a time to wait for the operation of playing back main data to be enabled can be reduced.
It should be noted, however, that in the case of a synchronous playback operation wherein an access to a sub-data area on the disc is made to read out a necessary sub-data file from the disc during a period in which an operation to transfer audio data from the disc to the buffer memory is paused in an intermittent playback of audio data described above, the optical head is moved between the main-data area and the sub-data area on the disc frequently in order to make accesses to the areas. In actuality, since the main-data area and the sub-data area on the disc are physically separated away from each other, the optical head itself needs to be moved by an operation of the sled mechanism in most cases.
The sled mechanism has a configuration wherein a sled shaft provided in the radial direction of the disc is typically driven by a motor into a rotation to move the optical head. That is why components such as a variety of gears are also provided.
When the sled mechanism is driven, mechanical operation sounds are generated by, among other causes, the rotations of the motor and the sled shaft. In an operation to play back main data and sub data in synchronization with the main data, the optical head is moved at a relatively high frequency between the main-data and sub-data areas to make accesses to the areas as described above. As a result, the frequency at which mechanical sounds are generated by the sled mechanism to accompany the accesses also increases to a comparatively high value.
For example, users who attach importance to the sound quality are of course conceivable. Such a user is quite happy to just thoroughly listen to reproduced audio data stored on a disc as main data without particularly watching sub-data played back from a sub-data file.
For example, when such a user is listening to audio data reproduced in a synchronous playback operation described above, the user may be bothered by mechanical sounds of the sled mechanism heard rather frequently even if the volume of the sounds is not so high.
Thus, when the user wants to listen to only audio data, for example, it is desirable to reduce the frequency of generation of mechanical sounds accompanying sled movements described above as much as possible.
It is thus an object of the present invention addressing the problems described above to provide a playback apparatus having a function for playing back main data and sub-data in synchronization with the main data wherein the function is utilized as effectively as possible to result in improvements in the amusement aspect and the functional aspect.
It is another object of the present invention addressing the problems described above to provide a playback apparatus for carrying out playback operations on a disc-shaped recording medium comprising: a main-data area for recording main data; a main-data management area for recording main-data management data for controlling said main data; a sub-data area for recording sub-data associated with said main data; and a sub-data management area for recording sub-data management data for controlling said sub-data, said playback apparatus characterized by comprising: a playback means for playing back said main data from said main-data area in accordance with said main-data management data recorded in said main-data management area and for playing back said sub-data from said sub-data area in accordance with said sub-data management data recorded in said sub-data management area; a transport means for transporting said playback means in a radial direction of said disc-shaped recording medium; a memory means for storing either said main data or said sub-data played back by said playback means; a control means for controlling said transport means to transport said playback means to either said main-data for recording said main data during a period to read out said sub-data or said sub-data area for recording said sub-data during a period to read out said main-data; and an operation means for specifying a first playback mode to play back said main data and said sub-data synchronously or a second playback mode to play back either said main data or said sub-data, wherein said control means inhibits transportation of said playback means by said transport means between said main-data area and said sub-data area when said second playback mode is specified by said operations means.
It is still another object of the present invention to provide a playback apparatus for carrying out playback operations on a disc-shaped recording medium comprising: a main-data area for recording main data; a main-data management area for recording main-data management data for controlling said main data; a sub-data area for recording sub-data comprising text data and still-picture data associated with said main data; and a sub-data management area for recording sub-data management data for controlling said sub-data, said playback apparatus characterized by comprising: a playback means for playing back data from said main-data area, said main-data management data, said sub-data area and said sub-data management area; an operation means for specifying: a first playback mode to play back said main data only; a second playback mode to synchronously play back said main data and said text data associated with said main data; a third playback mode to synchronously play back said main data, said text data and said still-picture associated with said main data; or a fourth playback mode to play back said still-picture data only; and a transport control means for transporting said playback means in a radial direction of said disc-shaped recording medium in accordance with a playback mode selected by said operation means.